PRESIDENTIAL ADDRESS. 501 
Introduced to Zoology when Haeckel and Gegenbaur were both at their 
zenith, I have been long enough a worker and teacher to feel elated by its 
progress and depressed by its shortcomings and failures. Perhaps we have gone 
too fast, carried along by methods which have yielded so much and therefore 
have made us expect too much from them. 
Gegenbaur founded the modern comparative anatomy by basing it upon the 
theory of descent. The leading idea in all his great works is to show that 
Transformation, ‘ continuous adjustment’ (Spencer), has taken place; he stated 
the problem of comparative anatomy as the reduction of the differences in the 
organisation of the various animals to a common condition; and as homologous 
organs he defined those which are of such a common, single origin. His first 
work in this new line is his classical treatise on the Carpus and Tarsus (1864). 
It followed from this point of view that the degree of resemblance in struc- 
ture between homologous organs and the number of such kindred organs 
present is a measure for the affinity of their owners. So was ushered in the 
era of pedigrees of organs, of functions, of the animals themselves. The tracing 
of the divergence of homogenous parts became all-important, whilst those organs 
or features which revealed themselves as of different origin, and therefore as 
analogous only, were discarded as misleading in the all-important search for 
pedigrees. Functional correspondence was dismissed as ‘mere analogy, and 
even the systematist has learnt to scorn these so-called physiological or adaptive 
characters as good enough only for artificial keys. A curious view of things, 
just as if it was not one and the same process which has produced and abolished 
both sets of characters, the so-called fundamental or ‘reliable’ as well as the 
analogous. 
As A. Willey has put it happily, there was more rejoicing over the discovery 
of the homology of some unimportant little organ than over the finding of the 
most appalling unrelated resemblance. Morphology had become somewhat in- 
tolerant in the application of its canons, especially since it was aided by the 
phenomenal growth of Embryology. You must not compare ectodermal with 
endodermal products. You must not make a likeness out of another germinal 
layer or anything that appertains to it, because if you do that would be a 
horror, a heresy, a homoplasy. 
Haeckel went so far as to distinguish between a true Homology, or Homo- 
phyly, which depends upon the same origin, and a false Homology, which applies 
to all those organic resemblances which derive from an equivalent adaptation to 
similar developmental conditions. And he stated that the whole art of the 
morphologist consists in the successful distinction between these two categories. 
If we were able to draw this distinction in every case, possibly some day the 
grand tree of each great phylum, maybe of the whole kingdom, might be recon- 
structed. That would indeed be a tree of knowledge, and, paradoxically enough, 
it would be the deathblow to classification, since in this, the one and only true 
natural system, every degree of consanguinity and relationship throughout all 
animated nature, past and present, would be accounted for; and to that system 
no classification would be applicable, since each horizon would require its own 
grouping. There could be definable neither classes, orders, families, nor species, 
since each of these conceptions would be boundless in an upward or downward 
direction. 
Never mind the ensuing chaos; we should at least have the pedigree of all 
our fellow creatures, and of ourselves among them. Not absolute proof, but the 
nearest possible demonstration that transformation has taken place. Empirically 
we know this already, since, wherever sufficient material has been studied, be it 
organs, species or larger groups, we find first that these units had ancestors and 
secondly that the ancestors were at least a little different. Evolution is a fact 
of experience proved by circumstantial evidence. Nevertheless we are not 
satisfied with the conviction that life is subject to an unceasing change, not 
even with the knowledge of the particular adjustments. We now want to under- 
stand the motive cause. First What, then How, and now Why? 
It is the active search for an answer to this question (Why?) which is 
characteristic of our time. More and more the organisms and their organs are 
considered as living, functional things. The mainspring of our science, perhaps 
of all science, is not its utility, not the desire to do good, but, as an eminently 
matter-of-fact man, the father of Frederick the Great, told his Royal Acade- 
